1. Field of the Invention
This invention relates to cat litter boxes, and in particular to a sanitary cat litter box and method of use.
2. Background of the Invention
It is believed in the scientific community that cats developed from a small animal which resembled a weasel called a Miacis. The Miacis lived more than 50 million years ago, and is also believed to be the ancestor of other mammals such as bears, dogs and raccoons.
It is not known when cats were first tamed, but many believe the ancient Egyptians first domesticated cats descended from African wildcats as early as 3500 BC. These cats killed mice, rats and snakes, thus preventing these pests from infesting Egyptian farms and granaries. By around 1500 BC the Egyptians started regarding cats as sacred. One of their gods was a goddess of love or fertility called Bastet or Bast, and comprised the head of a cat and the body of a woman. Harming cats was illegal, and killing a cat was punishable by death. Like humans who died, deceased cats were mummified; one ancient cat cemetery was found containing more than 300,000 cat mummies.
Mediterranean traders such as Greeks and Phoenicians probably brought cats to Europe and the Middle East ca. 1000 BC. The ancient Greeks and Romans regarded cats highly for their ability to hunt pests such as rodents. Cats became symbols of liberty, and were thought to be the spirit of the household in Rome.
As in Europe, cats gained popularity in the Middle East. Many libraries used them to protect manuscripts from damage caused by mice and rats. In addition, Middle Eastern cats protected silk worm cocoons from rodent attacks, thus contributing to the development of silk as a trading medium. In the Far East, cats became favorite subjects of writers and artists.
During the Middle Ages, Europeans started believing cats were agents of the Devil, and hundreds of thousands were killed. Unfortunately, this slaughter led to a large rise in the population of rats, which then spread the black plague throughout Europe, ultimately killing one quarter of the human population during the 1300's. By the 1600's the surviving Europeans once again realized the pest control value of cats, and cats traveled to the Americas with the colonists. Many cats living today in the United States and Canada are descendants of cats brought over from Europe during the 1600's and 1700's.
Today, cats are prized for their ability to hunt mice, rats and snakes, and to help maintain homes, farms and food storage buildings free from these pests. Additionally, cats can provide fine companionship, and many are kept as pets. More than 40 million domestic cats live in the United States, and more than two million in Canada. Cat care is a billion dollar industry, providing goods and services ranging from cat food, cat litter products, cat toys, veterinary services and cat grooming.
Due to the proliferation of apartments and homes with small yards, many cats in the United States are indoor cats, especially in urban areas. Thus, collection and disposal of cat waste in a clean, sanitary manner has become a major problem.
One wide-spread solution to the cat waste collection/disposal problem is the prior art cat litter box 102 depicted in FIG. 1. In use, prior art cat litter box top 104 is removed, and an impervious plastic liner containing clumping cat litter is placed inside prior art cat litter box bottom 106. Prior art cat litter box top 104 is than replaced, and a cat using prior art cat litter box 102 enters through the front opening, uses the facility, and then exits. The clumping cat litter absorbs urine and forms clumps in the presence of liquid, thus facilitating the removal of urine-soiled litter. Litter clumps and feces are removed using a slotted spoon, and theoretically the remaining litter is then clean enough for re-use.
A number of problems exist associated with prior art cat litter box 102 and its above-described method of use. First, cats tend to spray urine horizontally and even upwards during their ablution ritual. This leads to urine-encrusted litter box walls and even the ceiling becomes contaminated, though to a lesser extend than the walls. While the impervious bottom liner keeps prior art cat litter box bottom clean 106, no such protection exists for prior art cat litter box top 104, and so this latter component must be removed at least weekly, and its inside cleaned out. This chore can take at least 15-20 minutes per week, and sometimes more frequent cleanings are necessary.
Over a period of one year this ads up to around 20 hours spent cleaning the inside of prior art cat litter box top 104! Quite aside from this huge time waste, the chore is not a pleasant one--in fact, in the military latrine duty is actually used as a punishment for incompetence. If prior art cat litter box 102 is not kept clean, the cat(s) intended to use it will vociferously express their displeasure by meowing.
A second problem associated with prior art cat litter box 102 and its method of use is the time spent fishing around for litter clumps and cat feces with the slotted spoon. This activity constitutes a daily ordeal for urban cat owners, and requires several steps. First, prior art cat litter box top 104 must be removed. Second, litter clumps and feces must be visually identified. Third, the slotted spoon is brought into action, and each litter clump and lump of fecal matter be scooped up and placed in a trash receptacle. Finally, prior art cat litter box top 104 must be replaced onto prior art cat litter box bottom 106. Assuming 5 minutes per day expended on this chore, the average urban cat owner spends an astounding 29 hours per year, almost three quarters of a work week, sifting litter clumps and cat feces out of prior art cat litter box 102 with a slotted spoon!
Existing Designs
A number of approaches have been used to address the above problems. One of these is embodied in U.S. Pat. Nos. 5,980,452, 5,551,376, and 5,038,721 granted to Lundeen et al., Lundeen et al., and Ouellette et al. respectively. These patents taught a screen nested within the impervious liner. The screen had a mesh section sized to allow unsoiled litter to pass through the mesh apertures, but to not allow litter clumps and fecal matter lumps to pass through the mesh apertures. Thus, the screen could be removed from prior art cat litter box bottom 106, which action would remove any accumulated cat waste, and leave only unsoiled cat litter within prior art cat litter box 102. While these patents provided an easier way to remove cat litter from prior art cat litter box 102 than the conventional slotted spoon, they did not address the problem of urineencrusted litter box tops. In addition, they taught only one screen, which provided for only one use.
A second approach was disclosed in U.S. Pat. Nos. 5,325,815 and 4,615,300 granted to Gumpesberger and McDonough respectively. These patents taught a plurality of nested rigid screens which could be removed sequentially. While these inventions disclosed a more practical method of use for day-to-day cat waste removal, they were expensive and unwieldy. In addition, they did not teach a solution to the soiled litter box top problem.
Still another approach to the cat litter collection/disposal problem were advanced by a number of patents which disclosed a plurality of flexible sieves or sieve bags nested within the impervious liner. Patents representative of this approach include U.S. Pat. Nos. 5,752,466, 5,564,366, 5,207,772, 5,158,042, 5,062,392, 4312,295 and 3,809,013 granted to Lundeen et al., Hancock, Lauretta et al., Hammerslag et al., Lavash, Harrington and Rigney at al. Although these inventions disclosed a more practical method of use for day-to-day cat waste removal, they did not teach a solution to the soiled litter box top problem.